Engine starter gearing



Dec. 28, 1948'. r B. w. JONES 2,457,239

ENGINE STARTER GEARING- Filed Feb 10. 1947 s Sheets-Sheet 1 15 I INVENTOR.

WITNESS BY Dem 28 1948. 3, w, JONES 2,457,239

ENGINE STARTER GEARING Filed Feb. 10, 1947 vWTNEss:

ATTQRNEY 3 Sheets-Sheet 2 Dec. 28, 194s.- 5. w. JONES 2,457,239

' ENGINE STARTER GEARING Filed Feb. 10, 1947 3 Sheets-Sheet 3 INVENTOR.

I BY ww WITNESS! Patented Dec. 28, 1948 ENGINE STARTER. GEARING Burr W. Jones, ROChBStGI'fN." Y., assignor to Bendix Aviation Corporation, a corporation of Delaware Application February 10, 1947 Serial No. 727,544

Claims.

The present invention relates to engine starter gearing and more particularly to heavy duty gearing adapted to start large internal com-- bustion engines such as Diesel engines.

It is an object of the present invention to provide-a novel engine starter drive which is efilcient and powerful in operation while being comparatively small and economical to manufacture.

It is another object to provide such a device which provides a comparatively high ratio of gear reduction without producing localized or unbalanced stresses.

It i another object to provide such a device which is arranged to automatically engage a member of the engine to be started upon energization of the starting motor and disengage when the engine becomes self-operative.

It is another object to provide such a device in which the meshing of the starter pinion is efiected by a small amount of rotation of the starting motor, whereby the engagement takes place quietly and without excessive shock.

It is another object to provide such a device incorporating elastic elements which serve to cushion the initial actuation of the drive and to yieldingly arrest the longitudinal movement of the parts when they are returnedto idle position.

It is another object to provide such a device in which the reduction gearing is substantially enclosed by a driven internal gear member.

It is another object to provide such a device including a plurality of intermediate gears, and elastic members cooperating to equalize the load on said gears.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a side elevation, partly broken away and in section of a reduction gear drive constituting a preferred embodiment of the invention, showing the parts in idle position;

Fig. 2 is a similar view showing the parts in cranking position; 4 h

Fig. 3 is a section taken substantially on the line 33 of Fig. 1; Fig. 4 is a detail in perspective of the annular member joining the free ends of the'bearing bolts for the idler gears;

- Fig. 5 is a view similar to Fig. 1 of a second embodiment of the invention;

Fig. 6 is a view similar to Fig. 5 showing the parts in, cranking position; and

Fig. 7 is a section taken substantially on the line l-'I of Fig. 5.

In Fig. 1 of the drawing there is illustrated a portion of the frame I of a starting motor in which a power shaft 2 is journalled by means of a bearing 3, the outer end of the power shaft being supported in an outboard bearing 4 which. is rigidly attached to the motor frame in any suitable rnanner not illustrated. A spiral driving pinion 5 is fixedly mounted on the power shaft 2 as by means of a key 6 and lock ring I which latter hold-s said pinion against the bearing 3, the latter seating against a shoulder 8 on the power shaft. A plurality of spiral. idler gears 9 are slidably journalled by means of bearings I I on stub shafts I2 anchored as indicated at l3 in the motor frame I in position to maintain the idler gears in mesh with the drive pinion 5.

An internal spiral gear I4 is arranged to surround and mesh with the idlers 9 and is slidably journalled on the power shaft 2. A pinion I5. is formed on or rigidly-fiXed to the internal gear I4 and is arranged to be moved thereby into and out-of'mesh with a member such as a ring gear I6 of the engine to be started. A thrust ring I1 is' mounted in the open end of the ring gear I4 and retained therein by means of' a split lock ring I8 in position to engage the sides of the idler gears 9-to arrest the longitudinal movement of the ring gear toward the engine member and thereby define the meshed or cranking position of the pinion I5.

' The free ends of the idler bearing shafts I2 are provided with heads I9 which are arranged to be slidably received in pockets 2I formed in an annular plate member 22 (Fig. 4) which is slidably and rotatably mounted on the power shaft 2 within'the internal gear M. A plurality of rings 23 of elastically deformable material such asrubber are seated on the exteriors of said pockets 2| and are thereby located between the plate 22 and the idler gears 9, thrust washers 24. being preferably interposed between the bearings II of the idlers and said rubber rings. Spacing blocks 25 are mounted on the idler bearing shafts I2 to position the bearings I I laterally with respect to the motor frame I. Preferably, the dimensions of the parts are such that the rubber rings 23 are mounted under some initial compression, which holds the idler gear bearings I I against the spacing blocks as shown in Fig. 1.

In the operation of this embodiment of the invention, starting with the parts in the positions illustrated in Fig. 1, rotation of the power shaft in the direction of the arrow (a) causes the driving pinion 5 to rotate the idlers 9, the spiral teeth of which cooperate with the spiral teeth of the rubber rings 23 which yieldingly arrest the long i-e tudinal movement of the idler gears 9 caused by the longitudinal component of the force transmitted from the spiral teeth of the driving pinion to the spiral teeth of the idler gears. I

During the cranking operation, since the idler gears 9 are individually cushioned by the rubber rings 23, the idler gears adjust themselves longitudinally on their bearing shafts l2 against the pressure of the rubber rings 50 as to substantially equalize the torque transmitted through the idlers. Localized -stresses, and unbalanced-forces which might tend to overload the gearing are thus avoided. l

When the engine starts, the acceleration of the pinion 5 and internal gear :14 causes the internal gear to overrun the idlers 9 whereby the gear l4 and pinion l5 are returned to idle position. This demeshing movement is arrested by the engagement of the web 20 of the internal gear with the annular plate member 22. The shock of engagement is transmitted by the plate 22 to the rubber cushions 23 which thus serve to yieldingly arrest the demeshing movement of the ring gear.

In the embodiment of the invention illustrated in Fig. 5, a motor frame 5|, has a power shaft 52 'journalled therein by means of a bearing 53. Aldriving pinion 55 having an extended hub 56 is fixedly mounted on thepower shaft as by means of a key 51' and set screw 58. A pluralit of idler gears 59 are slidably journalled onbea-ring shafts 62 fixedly mounted at one end in the motor frame as shown at 63.

An annular cam and internal gear member 64 is arranged to surround and mesh with the idler gears '59 and is provided exteriorly with a spiral cam 65 which is slidably received in a spiral cam slot 66 in a rotatable housing, member 61.- The housing member is closed at one end by a web or flange member 58 which is rigidly attached as indicated at 6-9 to a pinion ll slidably journalled on the .power shaft .52 in position to move into and out of mesh with a ring gear 12 of the engine to be started.

The annular gear 64 has fixed thereto as indicated at 13 a thrust ring 14 which limits the longitudinal movement of the annular gear in a direction toward the engine member by engaging the sides of the idler gears 59. Movement in the opposite direction is prevented by a spacing member 15 mounted on the idler gear shafts 62 between the idler gears and the motor frame 5|.

A thrust ring 16 is mounted in the open end of the cam member 51, being retained therein by a split lock ring ll, said thrust ring being adapted to engage the side of the annular gear 64 and its thrust ring M to thereby arrest longitudinal movement of the cam member 61 and pinion H in the direction toward the engine gear 12. An annular plate member 18 is slidably journalled on the power shaft 52 within the cam member 51 and is provided with pockets l9 slidably receiving the heads 8| of idler bearing shafts 62. Cushion rings 82 of rubber or similar material are seated on the exteriors of the pockets 19 between the plate 18 and thrust washers 83, which latter bear on the idler gear shafts 62 against the idler gears 59.

The operation of this embodiment of the invention is substantially similar to the embodiment first described except that the thrust and torque transmitted by the idler gears 59 from the driving pinion 55 is applied to the housing member 61 through the annular gear and cam member 64. The spiral angle of the cam 65 may,

therefore, be selected for optimum performance as a translating means for the pinion H with complete freedom from sticking or jamming, while the spiral gearing may be designed to operate in conjunction with the rubber cushions 82 so as to properly-limit and damp the shocks and stresses 7 developed.

Although but two embodiments of the invention have been shown and described in detail.

it will be understood that other embodiments are possible and that various changes maybe made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is: I

1. In a heavy duty drive for engine starters, a power shaft, a spiral pinion fixed thereon, a plurality of spiral idler gears journalled =on fixed bearings meshing with said pinion with freedom for longitudinal movement, a spiral internal gear enclosing and meshingwith said idlers, and means actuated by said internal gear to engage and drive a member of an engine to be started.

2. .An engine starter drive as set forth in claim 1 including further, means for limiting the longitudinal movement of the internal gear with respect to the idler gears in the direction toward said engine member.

.3. An engine starter drive as set forth in claim 2 including further, yielding means for limiting the longitudinal movement of said idler gears in the direction toward said engine member.

4. An engine starter drive as set forth in claim 3 in which said yielding means includes a separate elastic cushion for each idler, serving to substantially equalize the loads on said idlers.

5. An engine starter drive as set forth in claim 3 including further, means cooperating with said yielding means to yieldingly limit longitudinal movement of the spiral internal gear in the direction away from the engine member.

6. In a heavy duty starter drive a power shaft, abearing therefor, a driving pinion fixed on the power shaft adjacent said bearing, a plurality of idler gears meshing with said pinion, means for rotatably supporting said idlers including a plurality of bearing shafts fixedly mounted at one end with respect to said bearing, an internal gear journalled on the power shaft enclosing and meshing with said idlers, having means for engaging and driving a member. of an engine to be started, and an annular member surrounding the power shaft within the internal gear having openings slidably receiving the free ends of said bearing shafts.

7. An engine starter drive as set .forth in claim 6, further characterized in that said bearing shafts have heads on their free ends, and said annular member has pockets receiving said heads, and including further, elastic cushion members surrounding the bearing shafts between said idlers and the engine member, said annular member being adapted to engage .and limit the travel of. the internal gear in the direction away from the engine member.

8. An engine starter drive as set forth in claim '7 including further, means on the internal gear adapted to engage said idlers to limit longitudinal movement of the internal gear with respect thereto in the direction toward the engine member.

9. In an engine starter drive, a power shaft, a pinion fixed thereon, a plurality of idler gears arranged circumferentially around said pinion and meshing therewith, an internal gear surrounding and meshing with the idlers, an engine engaging pinion slidably journalled on the power shaft and connected to be actuated by the internal gear, said internal gear and idlers having inclined teeth, and yielding means limiting longitudinal movement of the internal gear.

10. An engine starter drive as set forth in claim 9 in which said idler gears are mounted with freedom for longitudinal movement, and said limiting means include elements of elastically deformable material and means cooperating therewith to oppose longitudinal movement of the idler gears and thereby equalize the load thereon.

11. In a heavy duty engine starter drive, a power shaft, a helical driving pinion fixed thereon, an idler gear, means for rotatably mounting the idler gear in mesh with the driving pinion with freedom for longitudinal movement, an internal gear meshing with said idler with freedom for limited relative longitudinal movement, a driven pinion slidably journalled on the power shaft for longtudinal movement into and out of mesh with a gear of an engine to be started, means actuating the driven pinion from the internal gear, and yielding means for resisting longitudinal movement of the idler on its mounting means.

12. An engine starter drive as set forth in claim 11 incorporating a plurality of idler gears, and separate yielding means for resisting longitudinal movement of each idler, arranged to equitably divide the total cranking torque among the idler gears.

13. An engine starter drive as set forth in claim 11 including further, means for limiting longitudinal movement of the internal gear relative to the idler gear in the direction to mesh the driven pinion with the engine gear and means including said yielding means for resisting longitudinal movement of the internal gear in the opposite direction.

14. In a double reduction engine starter drive a power shaft, a helical driving pinion fixed thereon, an idler helical gear meshing with the driving pinion, a bearing for the idler helical gear permitting longitudinal movement thereof, a driven pinion sldably journalled on the power shaft for longitudinal movement into and out of mesh with a gear of an engine to be started, and means for translating and rotating the driven pinion including a cylindrical member fixed to the driven pinion having an inclined connection with the idler gear, and means for limiting longitudinal movement of the cylindrical member in a direction to mesh the driven pinion with the engine gear, said means including an elastically deformable member, and means cooperating with the elastic member for yieldably limiting longitudinal movement of the idler gear.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Oct. 14, 1940 

